Heat recovery Steam Generator (HRSG) doors are a necessary, but unpleasant feature of many industries, such as power generation. Typically, a HRSG access door is a large square door having a flange that runs the perimeter of the body of the door. This flange is bolted to a mating flange located on an insulation box mounted over the HRSG access port using a bolt and nut attachment mechanism that is threaded through a number of apertures located in both flanges. This configuration presents a number of problems.
First, there is typically a thermal sealing gasket that is placed between the two flanges when mounting the door. Since both flanges are flat, there is no way to accurately place, and replace, the thermal sealing gasket. Therefore technicians commonly resort to self-help solutions, such as the use of duct tape to “tape” the thermal sealing gasket to a flange. Further, since the thermal sealing flange is placed between the two flanges, and the HRSG access door is bolted to the HRSG access using a series of bolts, then the thermal sealing gasket needs to be perforated to match the bolt holes, thereby compromising both the thermal properties and sealing capabilities.
It has been noted that a common problem caused by heat cycling due to compromised thermal insulation due to perforations in the thermal sealing gasket is that weld points attaching the insulation box to the HRSG.
Thus there is a current and continuing need for an improved HRSG access door that reduces or eliminates many of the above discussed problems.